A complementary metal oxide semiconductor (CMOS) image sensor (CIS) simultaneously reads pixel signals generally on a line basis, and generates one image by repeating the reading control on the line basis.
The pixel signals contain various pieces of noise, and methods of removing the noise have been proposed.
The pixel signals include, for example, noise caused by variation of transistor characteristics or fluctuation of power supply voltage.
Then, technology for reducing the noise of pixel signals caused by the variation of transistors is proposed (see Patent Document 1).
In addition, some cases where fluctuation of power supply voltage during operation of a logic circuit affects image quality as noise have recently occurred, which is an obstacle against improvement of the image quality.
Countermeasures for inhibiting the fluctuation itself of power supply voltage have been conventionally undertaken by strengthening external parts and board wiring against the fluctuation of the power supply voltage.